An image forming apparatus such as an MFP (multifunction peripheral) executes a RIP (Raster Image Processor) process for converting data described in a PDL (Page Description Language) such as PostScript or PDF (Portable Document Format) to raster data for printing in some cases. The RIP processing includes an analysis processing and a drawing processing. The analysis processing includes a process to divide data of a plurality of pages into intermediate data of a plurality of single pages. The drawing processing includes a process to convert the intermediate data from the analysis processing to the raster data for printing. The raster data for printing is hereinafter referred to as printing data.
The image forming apparatus stores the data converted with the RIP processing in a storage device such as a memory or a HDD (Hard Disk Drive). However, in a case in which data which is a printing object is a color image with high resolution, the data is a very large size. For this reason, the image is stored after compression processing. Since software-based compression takes much time to execute, hardware-based compression using a compression core may be used in some cases.
The image forming apparatus includes a processor having a plurality of cores, such as a multi-core CPU (Central Processing Unit) or a CPU with a GPU (Graphics Processing Unit) built therein. The processor operates as a RIP and executes the analysis processing and the drawing processing in parallel by multithreading or the like to improve a speed of the RIP processing. However, even if the RIP processing speed executed by the processor improves, a speed of the compression process by the compression core becomes a bottleneck. Even if the drawing processing is carried out in parallel, if the compression core is not idle, there is waiting time for compression processing. In this case, a speed of the entire process including the RIP processing and the compression processing may not be shortened, while the usage ratio of the processor increases. Since the processor of the image forming apparatus executes various processes other than the RIP processing, there is a case in which processing speed of other tasks becomes slower if the usage ratio by the RIP processing increases too much.